Herbicidal pyrido(1,2-delta)-s-triazinediones

ABSTRACT

PYRIDO (1,2-A) -S-TRIAZINE-DIONES OF THE FORMULA   2,4-DI(O=),3-R2,8-R1,R3-3,4-DIHYDRO-2H-PYRIDO(1,2-A)-S-   TRIAZINE   WHEREIN:   R1 REPRESENTS HYDROGEN, HALOGEN, NITRO, LOWER ALKYL, LOWER ALKOXY, OR HALOGENALKYL, R2 REPRESENTS STRAIGHT - OR BRANCHED-CHAIN ALKYL, LOWER ALKENYL, LOWER ALKINYL, CYCLOALKYL, ALKOXYALKYL OR HALOGENALKYL, AND R3 REPRESENTS HYDROGEN, HALOGEN, NITRO, LOWER ALKYL, LOWER ALKOXY OR HALOGENALKYL,   ARE DISCLOSED AS HERBICIDALLY ACTIVE COMPOUNDS. A METHOD OF CONTROLLING UNDESIRABLE PLANT GROWTH WITH THE AID OF SUCH COMPOUNDS AND COMPOSITIONS CONTAINING THEM ARE ALSO DESCRIBED.

United States Patent 3,756,803 HERBICIDAL PYRIDO[l,2-DELTA]-s-TRIAZINE-DIONES ABSTRACT OF THE DISCLOSURE Pyrido[1,2'a]-s-triazine-diones of theformula wherein:

R represents hydrogen, halogen, nitro, lower alkyl, lower alkoxy, orhalogenalkyl,

R represents straightor branched-chain alkyl, lower alkenyl, loweralkinyl, cycloalkyl, alkoxyalkyl or halogenalkyl, and

R represents hydrogen, halogen, nitro, lower alkyl, lower alkoxy orhalogenalkyl,

are disclosed as herbicidally active compounds. A method of controllingundesirable plant growth with the aid of such compounds and compositionscontaining them are also described.

CROSS REFERENCE TO RELATED APPLICATION This is a division of applicationSer. No. 818,432, filed Apr. 22, 1969, now US. Pat. No. 3,609,148.

DESCRIPTION OF THE INVENTION The present invention relates to newpyrido[l,2-a]-striazine-diones, a process for the preparation of thesenew compounds, herbicidal agents which contain these pyrido-[1,2-a]-s-triazine-diones as the active substances, and a process forthe control of weeds and unwanted grasses using the new activesubstances or agents containing them.

More in particular, the invention provides new herbicidalpyrido[1,2-a]-s-triazine-diones of the Formula I:

wherein R represents hydrogen, halogen, nitro, lower alkyl, lower alkoxyor halogenalkyl,

R represents straightor branched-chain alkyl, lower alkenyl, loweralkinyl, cycloalkyl, alkoxyalkyl or halogenalkyl, and

R represents hydrogen, halogen, nitro, lower alkyl, lower alkOXy orhalogenalkyl.

In Formula I, lower alkyl radicals R and R include straight-chainradicals containing 1 to 5 carbon atoms, for example methyl, ethyl,n-propyl, isopropyl, n-butyl, tertbutyl, isobutyl or pentyl radicals.Lower alkoxy radicals Patented Sept. 4, I973 R and R also contain 1 to 4carbon atoms, for example, methoxy, isopropoxy, n-butoxy and isobutoxy.As halogenalkyl radicals R R and R are meant also lower alkyl radicalswhich are substituted one or more times by fluorine, chlorine and/orbromine. By straight-chain alkyl radical R are meant those having from 1to 8 and by branched-chain alkyl radicals R those having from 3 to 8carbon atoms, by lower alkenyl radical R those having from 2 to 4 carbonatoms, especially the allyl or methallyl radical and by lower alkinylradical R those having from 2 to 4 carbon atoms such as the propinyl orl-methylpropinyl radical. Cycloalkyl radicals R are monocyclic orpolycyclic aliphatic radicals containing 3 to 9 carbon atoms, forexample cyclopropyl, l-methyl-cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, bicyclohexyl, bicyclo-heptyl,bicyclo-octyl, tricyclononyl, tetra-cyclo-nonyl. Moieties forming a partof substituents, for example those in alkoxyalkyl, have each from 1 to 3carbon atoms. By halogen is meant, for R and R fluorine, chlorine orbromine.

The new pyrido[l,2-a]-s-triazine-diones of Formula I are preparedaccording to the invention by reacting one mol of a 2-aminopyridine ofFormula II with 3 mols of an isocyanate of Formula III:

R NCO (III) Pyrido[l,2-a]-s-triazine-diones of Formula I are obtained byanother process by reacting one mol of a pyridylcarbamic acid ester ofFormula IV in which R represents a lower alkyl radical with two mols ofan isocyanate of Formula III.

In the Formulae II to IV, the symbols R to R have the means given forFormula I. These reactions are preferably carried out in the presence ofbasic condensing agents and solvents or diluents which are inert, to thereactants. Suitable solvents are, for example, aromatic and aliphatichydrocarbons and halogenated hydrocarbons, N,N-dialkylated carboxylicacid amines, ether and etherlike compounds, nitriles etc. Pyridine andpyridine bases are particularly suitable as solvents for these reactionswith isocyanates, since they serve at the time time as basic condensingagents. Other tertiary amines, such as trialkylamines, may also serve asbasic condensing agents.

Pyrido[l,2-a]-s-triazine-diones of Formula I are also obtained byreacting a pyrido[1,2-a]-s-triazine-dione of Formula V with a strongbase and a compound of Formula VI,

hydrides, alkali metal borohydrides, alkali metal alcoholates and alkalimetal hydroxides. Further, the use of solvents or diluents such as werementioned above is advisable. The pyrido[l,2-a]-s-triazine-diones of theFormula V are converted into the corresponding alkali metal salts bysaid bases. The compounds of Formula VI are esters of hydrohalic acids,especially those of hydrogen chloride, hydrogen bromide and hydrogeniodide, and of sulphuric acid, for example, the corresponding alkyl,alkenyl, alkinyl and cycloalkyl halides or dialkyl sulphates. Aqueoussodium hydroxide solutions are preferably used as the strong base forthe reaction of a pyrido [1,2-a1-s-triazine-dione of Formula V with asulphate corresponding to Formula VI.

In addition, pyrido[l,2-a]-s-triazine-diones of Formula I can also beproduced when a N-pyridyl-urea of the Formula VII A N HCO-N HR U (VII)Rag N with haloformic acid alkyl esters, preferably ethylchloromethanoate, in the presence of a basic condensing agent.

The pyrido[l,2-a]-s-triazine-2,4-diones of Formula V mentioned asstarting substances were not previously known. These compounds may beprepared by reacting an aminopyridino of Formula VII withcarbo-ethoxy-isocyanate to give an ethyl allophanate of Formula VIIINH-iJ-NHC O 0:11,

Rag N VIII) and converting this into a pyrido[l,2-a]-s-triazine-2,4-dione of Formula V by ring closure with a basic condensing agent.Suitable basic condensing agents are inorganic bases, especially alkalimetal hydroxides.

The starting pyridyl-urea compounds of Formula VII may be prepared byreacting a Z-amino-pyridine of the Formula II with an isocyanate of theFormula III in a solvent or diluent inert to the reactants such as thoseusable for the reactions of compounds of the Formulae II and IV withisocyanates of the Formula III and optionally in the presence of a basiccondensing agent such as inorganic bases.

The new pyrido[1,2-a]-s-triazine-diones of the Formula I have excellentherbicidal properties and can be used for the control of monoanddi-cotyledonous weeds and unwanted grasses. In concentrations of 6kg./ha. and higher, the active substances according to the invention actas total herbicides, and in concentrations of less than 6 kg./ha., andpreferably less than 3 kg./ha. as selective herbicides. Types of weedwhich are difficult to control and those which are deep-rooting, forexample, grasses, Leguminosae and Umbelliferae are attacked by the newsubstances. The application of the active substances may be effectedwith the same good result, both in the preemergent and in thepost-emergent stages of the plants.

Those compounds of Formula I wherein R represents hydrogen or an alkylradical of 1 to 5 carbon atoms, R represents a branched-chain alkylradical of 3 to 8 carbon atoms or a cycloalkyl radical with 3 to 9carbon atoms, and R is hydrogen and more particularly those wherein Rrepresents a branched-chain alkyl radical linked to the triazine ring byway of the branched carbon atom such as for example, isopropyl,sec-butyl, tert-butyl, secpentyl, tert-pentyl and also a cycloalkylradical are particularly prefered.

Such active substances are selective and may serve for the control ofweeds in cultivated crops, for example for the control of types ofmillet (Panicum sp.), types of mustard (Sinapis sp.), types of goosefootor fat hen (Chenopodiaceae), annual meadow grass (poa annua), fieldfoxtailgrass (Alopecurus agrestis), camomile (Matricaria), parsnip(Paslinaca sativa), without damage to useful plants such as cereals,maize, root vegetables, oil plants, vegetables, cotton, sorghum, soyabeans and lucerne, before or after emergence.

For the preparation of herbicidal compositions, the active substancesare admixed with suitable carriers and/ or dispersing agents. In orderto broaden the sphere of action of the triazine derivatives according tothe invention, these agents may be mixed with other herbicides, forexample herbicides from the triazine series, such as halodiamino striazines, alkoxyand alklthiodiaminos-triazines, triazoles, diazinessuch as uracils, aliphatic carboxylic acids and halocarboxylic acids,halogenated benzoic acids and phenylacetic acids,aryloxyalkane-carboxylic acids, hydrazides, amides, nitriles, esters ofsuch carboxylic acids, carbamic acid and thiocarbamic acid esters, ureasetc.

Examples of such admiscible herbicidal substances are the followingcompounds:

2-chloro-4,6-bis- (ethylamino -s-triazine2-chloro-4-ethylamino-6-isopropylamino-s-triazine2-chloro-4,6-bis-(methoxypropylamino)-s-triazine2-methoxy-4,6-bis-(isopropylamino)-s-triazine2-diethylamino-4-isopropylacetamido-6-methoxy-striazine2-isopropylamino-4-methoxypropylamino-6-methylmercapto-s-triazine2-methy1mercapto-4,6-bis- (isopropylamino) -striazine2-methylmercapt0-4,6-bis-(ethylamino)-s-triazine2-methylmercapto-4-ethylamino-fi-isopropylaminos-triazine2-methoxy-4,6-bis-(ethylamino)-s-triazine2-methoxy-4-ethylamino-6-isopropylamino-s-triazine2-chloro-4,6-bis-(isopropylamino)-s-triazine5-bromo-3-sec.butyl-o-methyl-uracil 3-cyclohexyl-5,6-trimethylene-uracilS-amino-S-chloro-l-phenyl-pyridazone-(6)3,6-dioxo-1,2,3,6-tetrahydropyridazine dinitro-sec.butylphenyl and itssalts pentachlorophenol and its salts trichloroacetic acid and its salts2,2-dichloropropionic acid and its salts 2-chloro-N,N-diallylacetamidemaleic acid hydrazide 2,3,6-trichlorobenzoic acid and its salts2,3,5,6-tetrachlorobenzoic acid and its salts2-methoxy-3,5,6-trichlorobenzoic acid and its salts2-methoxy-3,-6-dichlorobenzoic acid and its salts3-amino-2,S-dichlorobenzoic acid and its salts3-nitro-2,S-dichlorobenzoic acid and its salts2-methyl-3,6-dichlorobenzoic acid and its salts 2,6-dichlorobenzonitrile2,6-dichlorothiobenzamide 2,3,G-trichlorophenylacetic acid and its salts2,4-dichlorophenoxyacetic acid and its salts2,4,S-trichlorophenoxyacetic acid and its salts and esters(2-methyl-4-chlorophenoxy)-acetic acid and its salts and esters2-(2,4,5-trichlorophenoxy)-propionic acid and its salts and esters 2-(2,4,5 -trichlorophenoxy) -ethyl-2,2-dichloropropionate4-(2,4-dichlorophenoxy)-butyric acid and its salts and esters4-(Z-methyl-4-chlorophenoxy)-butyric acid and its salts and esters2,3,6-trichlorobenzylxypropanol 4-amino-3,5,G-trichloropicolinic acidN'-cyclooctyl-N,N-dimethylurea 3-phenyl-1 l-dimethylurea 3-(4'-chlorophenyl) 1, l-dimethylurea 3- (3 -trifluoromethylphenyl)-1,1-dimethylurea 3-(3,4-dichlorophenyl)-1,1-dimethylurea 3-3',4'-dichlorophenyl) l-n-butyl-l-methylurea 3- 3,4-dichlorophenyl)-1,1,3-trimethylurea 3- (3 ',4'-dichlorophenyl)-1,l-diethylurea 3-(4'-chlorophenyl)-1-methoxy-1-methylurea3-(3',4-dichlorophenyl)-1-methoxy-l-methylurea 3-(4'-bromophenyl)l-methoxy-l-methylurea 3- 3',4-dichlorophenyl) -3-methoxy- 1,l-dimethylurea 3-(4'-chlorophenoxyphenyl)-1,1-dimethylureaN,N-di-(n-propyl)-S-ethyl-thiolcarbamic acid ester N,N-di- (n-propyl)-S-n-propyl-thiolcarbamic acid ester N-ethyl-N- (n-butyl)-S-n-propyl-thiolcarbamic acid ester N-phenyl-o isopropyl-carbamic acidester N-(m-chlorophenyD O-isopropyl-carbamic acid esterN-(m-chlorophenyl)-0 4-chlorobutin-(2)-yl-carbamic acid esterN-(3',4-dichlorophenyl)-O-methylcarbamic acid ester.

The following examples illustrate the process for the preparation of thenew compounds of Formula I. Provided nothing else is indicated, thetemperatures are given in degrees centigrade, and percentages are byweight.

Example 1 A. solution of 10.8 g. (0.1 mol) of 2-amino-3-methylpyridineand 41.5 g. (0.35 mol) of cyclohexyl isocyanate in 150 ml. of absolutepyridine is heated under reflux for 16 hours. After evaporation of thesolution in vacuo the residue is washed with ether on a suction filter.In order to separate the 1,3-dicyclohexylurea formed as byproduct, thefiltered material is extracted with methylene chloride and the filtrateis then filtered through a column of 100 g. of aluminium oxide (activityI). After evaporating the solution and recrystallising the residue frommethylene chloride-petrol ether, 19.3 (74.5%) of 3-cyclohexyl- 9-methyl2H pyrido [1,2-a]-s-triazine-2,4(3H)-dione, M.P. 179-180" are obtained.

Example 2 8.3 g. (0.05 mol) of 2-ethoxycarbonylarninopyridine aretreated with 9.4 g. (0.11 mol) of isopropyl isocyanate in 75 ml. ofabsolute pyridine. The mixture is boiled under reflux overnight. Afterevaporating the pyridine in vacuo, the residue is treated with ether andfiltered with suction. The crude product is purified by dissolving inmethylene chloride, filtering the solution through aluminium oxide(activity I) and recrystallising the residue after evaporation fromchloroform-ether. 4.0 g. (39%) of 3-isopropyl- ZH-pyrido[1,2-a]-s-triazine-2,4(3H)-dione, M.P. 181- 182, are thus obtained.

Example 3 1.95 g. (0.04 mol) of a marketed 50% dispersion of sodiumhydride in oil are made into a suspension with 6 absolute ether. Theether is separated and replaced by 40 ml. of absolute dimethylformamide. 6.5 g. (0.04 mol) ofZH-pyrido[1,2-a]-s-triazine-2,4(3H)-dione in 40 ml. of dimethylformamide are added to this suspension and the mixture is then stirredfor half an hour. 7.4 g. (0.04 mol) of isobutyl iodide are then addedand the mixture is heated at for 3 hours. The clear brown solution isevaporated in vacuo and the residue is treated with water and filtered.The crude product is purified by dissolving in methylene chloride,filtering through aluminium oxide (activity I), and the residue afterevaporation is recrystallised from methylene chloride-ether. The yieldis 3.3 g. (37.5%) of 3-isobutyl-2H-pyrido [1,2-a]-s-triazine-2,4(3H)-dione, M.P. 188-190.

Example 4 A solution of 8.15 g. (0.05 mol) of 2H-pyrido-[1,2-a]-s-triazine-2,4(3H)-dione in 27.5 ml. of 2 N caustic soda solution istreated at 15 with 6.95 g. (0.055 mol) of dimethyl sulphate and stirredfor 2 hours at room temperature. The crude product obtained byseparation and con centration of the mother liquor can be purified bysubliming at 200 (0.08 torr). Yield: 5.5 g. (63%) of 3- methyl-2H-pyrido[1,2-a]-s-triazine-2,4(3H)-dione, M.P. 251-252.

Example 5 A solution of 5.8 g. (0.025 mol) N-S-rnethylpyridyl-(2)-N'-cyclohexyl-urea in 50 ml. of absolute toluene are added dropwise,while stirring and cooling with ice water, to a solution of 5.0 g. (0.05mol) phosgene in 50 ml. of absolute toluene. The suspension so formed isthen refluxed for two hours and at the same time a weak stream ofphosgene is bubbled into the suspension. After cooling to roomtemperature, the precipitate formed is filtered with suction, suspendedin 200 ml. of water and the so formed suspension is neutralised withconcentrated ammonia. The precipitate is filtered off and dried. 5.85 g.of 3-cyclohexyl-9-methyl-2H-pyrido[l,2-a]-s-triazine-2,4(3H)-dione, M.P.179-180", are thus obtained.

Example 6 5.5 g. (0.023 mol) N-3-methylpyridyl-(2)-N'-cyclohexyl-ureasuspended in ml. of absolute toluene are refluxed with 25.3 g. (0.23mol) of chloroformic acid ethyl ester for 15 hours. The solution isevaporated and the remaining oily residue crystallises. The crystallineresidue is recrystallised from benzene-petrol ether. 3.1 g. (52.3%) of3-cyclohexyl-9-methyl-2H-pyrido[1,2-a]-striazine-2,4(3H)-dione of M.P.179-180 are obtained.

The 2H-pyrido[1,2-a]-s-triazine-2,4(3H)-dione used as starting materialfor Examples 3 and 4 is prepared as follows:

(a) 57.5 g. (0.5 mol) of ethoxycarbonyl isocyanate are allowed to dropat 10-15 with stirring into a solution of 47 g. (0.5 mol) of2-aminopyridine in 500 ml. of chloroform. The mixture is stirredovernight at room temperature, colourless crystals being precipitated.The precipitate is separated. On recrystallising the crude product andthe residue from evaporation of the filtrate from 400 ml. of ethanol,88.4 g. (85%) of 3-pyridyl-(2)- allophanic acid ethyl ester of M.P.142-144 are obtained.

(b) A solution of 52.3 (0.25 mol) of 3-pyridyl-(2')- allophanic acidethyl ester in 275 ml. of N-caustic soda solution is stirred for 15minutes at 60. After cooling to room temperature, the product isacidified with 20 ml. of glacial acetic acid, the colourless precipitateis separated and washed with a little cold Water. The 2H-pyrido-[1,2-a]-s-triazine-2,4(3H)-dione (37.1 g.=91%) thus obtained issufficiently pure for the further reactions. A preparation for analysispurified by recrystallising from Water shows a transition point at213-216".

The =N-3-methylpyridyl-(2)-N-cyclohexyl urea used as starting substancefor Examples 5 and 6 is prepared according to the process describedunder (a) but using 62.5

g. (0.5 mol) cyclohexylisocyanate instead of 57.5 g. ofethoxycarbonylisocyanate.

The following active substances of general Formula I were prepared in ananalogous way to that described in Examples 1 to 6.

one.

3-[0etahydro-1 ,2 ,4'-metheno-pentaleny1-(5)]-2H-pyrido[1,2-a1-s-triazine-2,4(3H) -dione 169. -171pyrido[1,2-a1-s-trlazine2,4(3H)-dione 125-1283-cyc1oocty1-2H-pyrido[1,2-a]-s-triazine-2, 138-1403-cyclooetyl-Q-methyl-ZH-pyndo[1,2-a1-s-triazine-2 4( dione 135-1373-eyelopropyl-2H-pyrido[1,2,21]-s-trlazine 207-209 e 102-1033-cyclopentyl-9-methyl-2H-pyrido[1, 2-a]-s-triazine-2,4 (3H) dlona170-172 3-isopropyl-Q-ethyl-ZH-pyrido [1 2-a]-s-tn'azine-2,4 (3H) -dione145-150 3-eyclohexyl-9-ethyI-ZH-pyrido [1 2-a1-s-tri mine-2,4 (3H) dione168-171 3-(1,3-dimetl1y1butyl) -2H-pyrido [1 2-a]-s-triazine-2,4 (3H)(hone 97-99 3- (1 ,3-dimethylbutyl)-9-methyl-2H-pyrldo[1,2-a1-s-triazine- 2,4(3H)-dione 93-053-cye1opropyl-O-m ethyl-2H-pyrido [1,2-a1-s-tri twine-2,4611)- dione174-176 3-isopropyl-7-nitro-2H-pyri do [1 2-a1-s-tri azi ne-2,4 (3H)-diono 101-104 3-iso pro pyl-9-nltro-2H-pyrido[1,2-a1-s-triazine-2 4(3H)-dione 3-eye1ohexyl-9-trifiuoromethyl-ZH-pyrido[1,2-a -s-trlazine-2,4

(3H)dione T a-igtiipropyl-o-n-pentyl-2H-pyr1do[1,2-a]-s-triazine-2,4(3H)3-(2-chlorethy1) -2H-pyrido[1 ,2-a]-s-triazine-2,4 (3H) -dione3-cyclohexyl-7-methoxy-2H-pyrido[1,2-a]-s-triazine-2,4(3H)- dione3-cyelo0cty1-7-trifluoromethyl-ZH-pyrido[1 ,2-a1-s-triazine-2,4(3H)-dione 8-propinyl-2H-pyrido[1 ,2-a]-s-tn'azine-2,4 (3H) -dione.S-biicyelo [4, 1 ,01-heptyl-(7') -2H-pyrido[1 ,2-a]-s-tri azine-2,4(3H l0110 on 3-propoxypropyl-2H-pyrido[1,2raltriazin The preparation ofherbicidal compositions according to the invention is carried out inknown way by intimate mixing and grinding of active substances of theGeneral Formula I with suitable carriers, possibly with addition ofdispersing agents or solvents inert towards these active substances. Theactive substances may be used in the form of dusts, scattering agents,granulates, coated granulates, impregnated granulates, homogenousgranulates, wettable powder pastes, emulsions, solutions or aerosols.

In order to prepare solid finished products (dusts scattering agents,granulates) the active substances are mixed I with solid carriers. Thegranular size of the carrier is suitably up to about 0.1 mm. for dusts,about 0.075 to 0.2 mm. for scattering agents and 0.2 mm. or over forgranulates. The concentration of the active substance in the solidfinished product usually amounts to 0.5 to To these mixtures may also beadded substances for stabilising the active substance and/or non-ionic,anionic and cationic substances, which, for example, improve theadhesion of the active substances to plants and parts of plants(adhesives and agglutinants) and or ensure a better wettability (wettingagents) and dispersability (dispersing agents).

Concentrates of active substances dispersible in water, Wettablepowders, pastes and emulsion concentrates are products which can bediluted with water to any desired concentration. They consist of activesubstance, carrier, possibly additives for stabilising the activesubstance, surface-active substances and anti-foaming agents, andpossibly solvents. The concentration of active substance in theseproducts amounts to 5 to 80%. The wettable powders and pastes areobtained by mixing and grinding the active substances with dispersingagents and pulverulent carriers in suitable devices until the productsare homogeneous. In some cases it is advantageous to use mixtures ofditferent carriers. The anti-foaming agents may, for example, besilicones. The active substances are so mixed, ground, sieved andclassified with the abovementioned additives that in the wettablepowders the solid fraction does not exceed a grain size of 0.02 to 0.04and in pastes does not exceed 0.003 mm. Dispersing agents, organicsolvents and water are used for the preparation of emulsion concentratesand pastes. The solvents must be practically colourless, non-phytotoxic,inert towards the active substances and not easily combustible.

Further, the compositions according to the invention may be applied inthe form of solutions. For this purpose, one or more of the activesubstances of the General Formula I is or are dissolved in suitableorganic solvents, mixtures of solvents or water. The solutions shouldcontain the active substances within a range of concentration from 1 to20% calculated on the total weight of the solutions.

Other biocidal active substances or agents can be admixed with theagents described according to the invention. Thus, in addition to thesaid compounds of the general Formula I and other herbicides, the newagents may contain for example, insecticides, fungicides, bactericides,fungistatic and lbacteriostatic substances or nematocides in order tobroaden the sphere of active. The compositions according to theinvention may also contain plant fertilisers, trace elements etc. In thefollowing compositions according to the invention, all percentages aregiven by weight.

GRANULATE The following substances are used for the preparation of a 5%granulate:

Parts 3 cyclohexyl 8 methyl 2H-pyrido-[l,2-a]-striazine-2,4(3H)-dione 5Epichlorhydrin 0.25 Cetylpolyglycolether with 8 mol ethyleneoxide 0.25Polyglycol (Carbowax) 3.50 Kaolin (grain size 0.3-0.8 mm.) 91.0

The active substance is mixed with epichlorhydrin and dissolved with 6parts of acetone, then polyglycol and cetylpolyglycolether are added.The solution so obtained is sprayed on kaolin and then the acetone isevaporated in vacuo.

9 WETTAB-LE POWDER The following components are used for the preparationof (a) a 50%, (b) a 25% and (c) a 10% wettable powder:

Parts 3 cyclohexyl 8-methyl-2H-pyrido[1,2-a]-s-triazine- 2,4(3H)-dione50 Sodium dibutylnaphthylsulphonate Naphthalenesulphonicacids-phenolsulphonic acids- Formaldehyde condensate in the proportion3:2:1 3 Kaolin 20 Champagne chalk 22 3 isopropyl 2Hpyrido[1,2-a]-s-triazine-2,4(3H)- dione 25 Oleylmethyltauride-sodiumsalt 5 Naphthalenesulphonic acid formaldehyde-conden- The said activesubstance is added to the corresponding carrier (kaolin and chalk) andis then mixed and ground. A wettable powder of excellent wettability andsuspensilbility is obtained. By dilution with water, suspensions of anydesired concentration of active substance can be obtained from suchwettable powders. Such suspensions may be used for control of weeds andunwanted grasses in cotton plants.

PASTE The following substances are used for the preparation of a 45%paste:

Parts 3 isoamyl 2H pyrido[1,2-a]-s-triazine-2,4(3H)- dione 45 Sodiumaluminium silicate 5 Cetylpolyglycolether (Genapol 0 080) 14Cetylpolyglycolether (Genapol O 050) 1 Spindle oil 2 Polyglycol(Carbowax) Water 23 The active substance is intimately mixed and groundwith the additive substances in suitable devices. A paste is obtainedfrom which suspensions of any desired concentration can be prepared bydilution with water.

EMULSION CONCENTRATE For the preparation of a 10% emulsion concentrate,

. 1 Parts 3' isopropyl 9 methyl 2H-pyrido[1,2-a]-s-triazine2,4(3H)-dione 10 Condensation product of octadecenol and ethylene oxidein a molar ratio of 1:8 Isophorone (3,5,S-trimethylcyclohex-Z-en-l-one)75 are mixed together. This concentrate can be diluted with water togive emulsions of suitable concentrations. Such emulsions are suitablefor the control of weeds in cultivated crops, as for example cottonmaize etc.

1 0 The herbicidal action of the pyrido[l,2-a]-s-triazinediones is shownin the following test reports:

TEST SUBSTANCES (1) 3 n butyl-2H-pyrido[1,2-a]-s-triazine-2,4(3H)- dione(2) 3 isobutyl 2H pyrido[1,2-a]-s-triazine-2,4(3H)- dione (3) 3isopropyl 2H pyrido[1,2-a]-s-triazine-2,4(3H)- dione (4) 3 isopropyl 9methyl 2H pyrido[1,2-a]-striazine-2,4(3H)-dione (5 3 isopropyl 9ethyl-2H-pyrido[1,2-a]-s-triazine- 2,4(3H)-dione (6) 3 sec-butyl 9methyl-2H-pyrido[l,2-a]-s-triazine- 2,4(3H)-dione (7) 3 (1',3 dimethylbutyl) 9 methyl 2H-pyrido [1,2-a] -s-triazine-2,4( 3H -dione (8) 3cyclopropyl 2H pyrido[l,2 a]-s-triazine-2,

4(3H)-dione (9) 3 cyclopropyl '9 methyl2H-pyrido[1,2-a]-s-triazine-2,4(3H)-dione (10) 3 cyclopentyl 2Hpyrido[1,2-a]-s-triazine-2,4-

(3H)-dione (11) 3 cyclopentyl 9 methyl2H-pyrido[1,2-a]-striazine-2,4(3H)-dione (12) 3 cyclohexyl 2Hpyrido[1,2-a] s-triazine-2,4-

(3H)-dione (13) 3 cyclohexyl 9 methyl2H-pyrido[1,2-a]-striazine-2,4(3H)-dione (14) 3 cyclooctyl 2H pyrido[1,2a]-s-triazine-2,4-

(3H)-dione (15) 3 [octahydro 1',2',4'-methano-pentalenyl-(5')]- 2Hpyrido[ 1,2-a] -s-triazine-2,4( 3H)-dione (16) 3 [octahydro 1',2',4'metheno-pentalenyl-(S')1- 9 methyl 2H pyrido [1,2-a]-s-triazine-2,4(3H)-dione METHOD The active substance is mixed with talcum in the ratio 1:9and added to garden soil, so that the concentration of active substanceis 0.5 g. per liter of soil. The following test plants are then sown inpots containing the prepared soil: oats, mustard, rye grass, sugarbeets, cucumbers, vetch. The pots are then kept in daylight in agreenhouse at 20 to 24 C. and 70% relative humidity.

The test plants are evaluated after 20 days and the evaluation isexpressed according to the following scale:

10=plants undamaged=untreated plants 0=complete destruction of allplants 9-1=intermediate degrees of damage RESULTS Active Rye SugarCucumsubstance Oats grass Mustard beets ber Veteh FIELD TESTS (SELECTIVEEFFECT) (a) Pre-emergence test The following test plants are sown in afreshly prepared secdbed: Vicia faba, peas, lucerne and flax. The activesubstance, as an aqueous dispersion prepared from a 25% wettable powder,is applied to the surface of the soil directly after sowing.

1=no symptoms or damage (same as untreated cultivated plants)2-4-=logarithmic increase of reversible phytotoxic symptoms58=logarithmic symptoms 9=complete destruction increase of irreversiblephytotoxic The herbicidal effect on the weeds is given in percent:

100% =complete destruction 90-10%-=intermediate degrees of destruction=no damage (same as untreated control plants).

Application concentration (in a.

kg Active Cultivated plants substance 4 3 2. 2 1. 5

Vista faba "5 g g a 3 4 3 2 1 1 1 Peas 1a 2 1 1 1 1 Lucerne. 12 2 32 g13 1 1 1 1 Herbicldal efieet on indige- 4 100 98 98 95 90 nous weeds (inpercent). 13 98 90 90 80 70 (b) Pre-emergence test with planted weedsThe cultivated plants maize, sunflowers and carrots and, as difficultlycontrollable weed Galium spec., rye grass and Amaranthus spec. were sownas test plants in a freshly prepared seedbed. Directly after sowing, theactive substance, in the form of an aqueous dispersion prepared from 25%wettable powder, was applied to the surface of the ground, to obtain theconcentrations in kg. per ha. given in the following table. After 54days the phytotoxic effect on the cultivated plants and the herbicidaleffect on the weeds that had been sown are evaluated:

The evaluation of the cultivated plants was determined according to thefollowing scale:

increase of irreversible phytotoxic The herbicidal effect on the weedsis given in percent:

100%=complete destruction 90-10% =intermediate degrees of destruction0%=no damage (same as untreated control plants).

For this test the following active substance was used: 3 isopropyl 9methyl-2H-pyrido[l,2-a]-s-triazi.ne-2,4 (3H)-dione (active substance 4).

RESULTS (A) Efiect on cultivated plants Application concentrations (inkgJha.)

Cultivated plants 5 4 3 2. 5 2

Maize 1 1 1 1 1 Sunflower 4 4 4 4 3 (B) Eflect on weeds Applicationconcentrations (in kg./ha.)

Woods 6 4 3 2. 5 2

Galium 90 9O 90 90 Rye grass 90 90 90 90 90 Amaranthus. 100 100 90 90Conclusions Both tests show that the active substances 4 and 13according to the instant application possess very good herbicidalactivity, both against indigenous weeds as well as against thedifiicultly controllable weeds which had been sown. The cultivatedplants showed no, or if any, then only slight, but reversible phytotoxicsymptoms.

We claim:

1. A herbicidal composition comprising an agriculturally acceptablecarrier and a herbicidally effective amount of a compound of the formulaR represents a member selected from hydrogen, halogen, nitro, loweralkyl, lower alkoxy and halogenlower alkyl,

R represents a member selected from straight-chain alkyl of from 1 to 8carbon atoms, branched-chain alkyl of from 3 to 8 carbon atoms, loweralkenyl, lower alkynyl cycloalkyl of from 3 to 9 carbon atoms,alkoxyalkyl of from 3 to 6 carbon atoms and halogen lower alkyl, and

R represents a member selected from hydrogen, halogen, nitro, loweralkyl, lower alkoxy and halogen-lower alkyl.

2. A composition as defined in claim 1, wherein in the compound, Rrepresents hydrogen or alkyl of from 1 to 5 carbon atoms, R representsbranched-chain alkyl of from 3 to 8 carbon atoms or cycloalkyl of from 3to 9 carbon atoms, and R is hydrogen.

3. A composition as defined in claim 2, wherein said compound is3-cyclohexyl-9-methyl-2H-pyrido[l,2-a]-striazine-2,4 3H) -dione.

4. A composition as defined in claim 2, wherein said compound is3-isopropyl-9-methyl-2H-pyrido[1,2-a]-s-triazine-2,4(3H)-dione.

5. A composition as defined in claim 2, wherein said compound is3-sec-butyl-9-methyl-2H-pyrido[l,2-a]-s-triazine-2,4(3H)-dione.

6. A method for controlling weeds which comprises applying to said weedsa herbicidally amount of a compound of the formula:

N-Rg

W he! e111 of from 3 to 6 carbon atoms and halogen lower alkyl,

and R represents a member selected from hydrogen, halogen, nitro, loweralkyl, lower alkoxy and halogen-lower alkyl.

7. A method according to claim 6 in which, in the compound, R representshydrogen or alkyl of from 1 to 5 carbon atoms, R representsbranched-chain alkyl of from 3 to 8 carbon atoms or cycloalkyl of from 3to 9 carbon atoms and R is hydrogen.

8. The method according to claim 7 in which the compound is 3-cyclohexyl9 methyl-2H-pyrido[1,2-a]-s-triazine-2,4(3H)-dione.

9. The method according to claim 7 in which the compound is 3-isopropy1-9 methyl-2H-pyrido[l,2-a]-s-triazine-2,4(3H)-dione.

10. The method according to claim 7 in which the compound is3-sec.-butyl-9-methyl-2H-pyrido[1,2-a1-s-triazine-2,4(3H)-dione.

References Cited UNITED STATES PATENTS 3,352,662 11/1967 Klopping -0-.-71 -93 3,544,570 12/1970 Timmler. 71-93 JAMES 0. THOMAS, JR., PrimaryExaminer

